Method and device for evaluating oscillation risk of wind power plant convergence system
阅读说明：本技术 一种用于评估风电场汇集系统振荡风险的方法及装置 (Method and device for evaluating oscillation risk of wind power plant convergence system ) 是由 赵岳恒 胡凯 周俊东 陈宇 钱纹 王志敏 王凌谊 张秀钊 刘民伟 赵爽 于 2019-10-28 设计创作，主要内容包括：本申请实施例公开了一种用于评估风电场汇集系统振荡风险的方法及装置,在该方法中,首先获取风电场汇集系统的规划方案,然后针对次/超同步频段,获取风电场汇集系统规划方案的所有谐振模式,以及获取所有谐振模式中的衰减因子,根据所述衰减因子的大小,判断每一种电网规划方案以及每一种风电场并网规划方案是否存在振荡风险,并且评估每一种电网规划方案以及所述每一种风电场并网规划方案的稳定性。本申请公开的方法中针对每一种电网规划方案以及风电场并网规划方案进行分析,不仅能够判断每种方案是否存在振荡风险,还能评估每种方案的稳定性,为实际风电场并网操作选取稳定性较好的规划方案,具备较强的工程实用性。(The embodiment of the application discloses a method and a device for evaluating oscillation risk of a wind power plant collection system. According to the method, each power grid planning scheme and each wind power plant grid-connected planning scheme are analyzed, whether oscillation risks exist in each scheme can be judged, the stability of each scheme can be evaluated, the planning scheme with good stability is selected for actual wind power plant grid-connected operation, and the method has strong engineering practicability.)
1. A method for assessing the risk of oscillation of a wind farm collection system, comprising:
acquiring a planning scheme of a wind power plant collection system, wherein the planning scheme of the wind power plant collection system comprises a plurality of power grid planning schemes and a plurality of wind power plant grid-connected planning schemes, the power grid planning schemes comprise grid planning of a power grid and parameters of power equipment in the power grid, and the wind power plant grid-connected planning schemes comprise grid-connected point position planning of a wind power plant and equipment parameters in the wind power plant;
acquiring all resonance modes of a planning scheme of a wind power station collection system aiming at a secondary/super-synchronous frequency band, wherein the resonance modes comprise a resonance mode of each power grid planning scheme and a resonance mode of each wind power grid-connected planning scheme;
obtaining attenuation factors in all resonance modes;
and judging whether each power grid planning scheme and each wind power plant grid-connected planning scheme have oscillation risks or not according to the attenuation factor, and evaluating the stability of each power grid planning scheme and each wind power plant grid-connected planning scheme.
2. The method of claim 1, wherein the obtaining all resonance modes of the wind farm collection system planning scheme for the sub/super synchronization frequency band comprises:
acquiring an s-domain equivalent circuit of a wind power plant collection system under each power grid planning scheme aiming at a sub/super synchronous frequency band, and acquiring an s-domain equivalent circuit of the wind power plant collection system under each wind power plant grid-connected planning scheme aiming at the sub/super synchronous frequency band;
constructing an s-domain node admittance matrix of the wind power plant convergence system under each power grid planning scheme according to the s-domain equivalent circuit of the wind power plant convergence system under each power grid planning scheme, and constructing an s-domain node admittance matrix of the wind power plant convergence system under each wind power plant grid-connected planning scheme according to the s-domain equivalent circuit of the wind power plant convergence system under each wind power plant grid-connected planning scheme;
acquiring determinant zero roots of an s-domain node admittance matrix, wherein the determinant zero roots comprise determinant zero roots of an s-domain node admittance matrix of a wind power plant collection system under each power grid planning scheme and determinant zero roots of an s-domain node admittance matrix of the wind power plant collection system under each wind power plant grid-connected planning scheme;
and acquiring all resonance modes of each power grid planning scheme and all resonance modes of each wind power grid-connected planning scheme according to the determinant zero root of the s-domain node admittance matrix.
3. The method of claim 2, wherein the obtaining attenuation factors in all resonant modes comprises:
acquiring the real part opposite number of determinant zero roots of the s-domain node admittance matrix;
and obtaining attenuation factors of all resonance modes in each power grid planning scheme and attenuation factors of all resonance modes in each wind power grid-connected planning scheme according to the real part opposite number of determinant zero roots of the s-domain node admittance matrix.
4. The method according to claim 3, wherein the judging whether each power grid planning scheme and each wind farm grid-connected planning scheme have oscillation risks according to the attenuation factor, and the evaluating the stability of each power grid planning scheme and each wind farm grid-connected planning scheme comprises:
acquiring minimum attenuation factors of all resonance modes in a target power grid planning scheme and minimum attenuation factors of all resonance modes in a target wind power plant grid-connected planning scheme, wherein the target power grid planning scheme is any one power grid planning scheme, and the target wind power plant grid-connected planning scheme is any one wind power plant grid-connected planning scheme;
judging whether the minimum attenuation factors of all the resonant modes in the target power grid planning scheme are smaller than 0, if so, judging that the target power grid planning scheme has an oscillation risk; judging whether the minimum attenuation factors of all the resonant modes in the target wind power plant grid-connected planning scheme are smaller than 0, if so, judging that the target wind power plant grid-connected planning scheme has an oscillation risk;
evaluating the stability of the target power grid planning scheme according to the minimum attenuation factor of all the resonance modes in the target power grid planning scheme; and evaluating the stability of the target wind power plant grid-connected planning scheme according to the minimum attenuation factors of all the resonance modes in the target wind power plant grid-connected planning scheme.
5. The method of claim 1, wherein the sub/super sync band is in a range of 10Hz to 100 Hz.
6. Device for assessing the risk of oscillations of a wind farm collection system, characterized in that it is applied to a method for assessing the risk of oscillations of a wind farm collection system according to claims 1-5, said device comprising:
the planning scheme acquisition module is used for acquiring a planning scheme of a wind power plant collection system, wherein the planning scheme of the wind power plant collection system comprises a plurality of power grid planning schemes and a plurality of wind power plant grid-connected planning schemes, the power grid planning schemes comprise grid planning of a power grid and parameters of power equipment in the power grid, and the wind power plant grid-connected planning schemes comprise grid position planning of a wind power plant and equipment parameters in the wind power plant;
the system comprises a resonance mode acquisition module, a power grid planning module and a power grid synchronization planning module, wherein the resonance mode acquisition module is used for acquiring all resonance modes of a planning scheme of a wind power station collection system aiming at a sub/super synchronous frequency band, and the resonance modes comprise a resonance mode of each power grid planning scheme and a resonance mode of each wind power grid synchronization planning scheme;
the attenuation factor calculation module is used for acquiring attenuation factors in all the resonance modes;
and the risk evaluation module is used for judging whether each power grid planning scheme and each wind power plant grid-connected planning scheme have oscillation risks or not according to the attenuation factor, and evaluating the stability of each power grid planning scheme and each wind power plant grid-connected planning scheme.
7. The apparatus of claim 6, wherein the resonant mode acquisition module comprises:
the system comprises an s-domain equivalent circuit establishing unit, a sub/super synchronous frequency band acquiring unit and a sub/super synchronous frequency band acquiring unit, wherein the s-domain equivalent circuit establishing unit is used for acquiring an s-domain equivalent circuit of a wind power plant collecting system under each power grid planning scheme aiming at the sub/super synchronous frequency band and acquiring an s-domain equivalent circuit of the wind power plant collecting system under each wind power plant grid-connected planning scheme aiming at the sub/super synchronous frequency band;
the s-domain node admittance matrix construction unit is used for constructing an s-domain node admittance matrix of the wind power plant convergence system under each power grid planning scheme according to the s-domain equivalent circuit of the wind power plant convergence system under each power grid planning scheme, and constructing an s-domain node admittance matrix of the wind power plant convergence system under each wind power plant grid-connected planning scheme according to the s-domain equivalent circuit of the wind power plant convergence system under each wind power plant grid-connected planning scheme;
the zero root calculation unit is used for acquiring a determinant zero root of an s-domain node admittance matrix, wherein the determinant zero root comprises the determinant zero root of the s-domain node admittance matrix of the wind power plant collection system under each power grid planning scheme and the determinant zero root of the s-domain node admittance matrix of the wind power plant collection system under each wind power plant grid-connected planning scheme;
and the resonance mode acquisition unit is used for acquiring all resonance modes of each power grid planning scheme and all resonance modes of each wind power grid-connected planning scheme according to the determinant zero root of the s-domain node admittance matrix.
8. The apparatus of claim 7, wherein the attenuation factor calculation module comprises:
the inverse number calculation unit is used for acquiring the inverse number of the real part of the determinant zero root of the s-domain node admittance matrix;
and the attenuation factor acquisition unit is used for acquiring attenuation factors of all resonance modes in each power grid planning scheme and attenuation factors of all resonance modes in each wind power grid-connected planning scheme according to the real part opposite number of determinant zero roots of the s-domain node admittance matrix.
9. The apparatus of claim 8, wherein the risk assessment module comprises:
the minimum attenuation factor acquisition unit is used for acquiring minimum attenuation factors of all resonance modes in a target power grid planning scheme and minimum attenuation factors of all resonance modes in a target wind power plant grid-connected planning scheme, wherein the target power grid planning scheme is any one power grid planning scheme, and the target wind power plant grid-connected planning scheme is any one wind power plant grid-connected planning scheme;
the risk judgment unit is used for judging whether the minimum attenuation factors of all the resonance modes in the target power grid planning scheme are smaller than 0 or not, and if yes, judging that the target power grid planning scheme has an oscillation risk; judging whether the minimum attenuation factors of all the resonant modes in the target wind power plant grid-connected planning scheme are smaller than 0, if so, judging that the target wind power plant grid-connected planning scheme has an oscillation risk;
the stability evaluation unit is used for evaluating the stability of the target power grid planning scheme according to the minimum attenuation factor in all the resonance modes of the target power grid planning scheme; and evaluating the stability of the target wind power plant grid-connected planning scheme according to the minimum attenuation factor in all the resonance modes of the target wind power plant grid-connected planning scheme.
Technical Field
The application relates to the technical field of wind power plant grid connection, in particular to a method and a device for evaluating oscillation risk of a wind power plant collection system.
Background
At present, wind power generation is in a state of rapid development in China, and a large wind driven generator is directly connected to a power grid to operate and can transmit strong electric power to the power grid. The wind power station convergence system formed by merging the wind power station into the power grid has oscillation risks, oscillation accidents caused by subsynchronous/supersynchronous oscillation of multiple causes occur in the wind power station convergence system in northwest areas of China, and the oscillation accidents cause that the power system has huge unstable risks, so that subsynchronous/supersynchronous oscillation risk evaluation needs to be carried out on a planning scheme for grid connection of the wind power station before the wind power station convergence system is put into operation to ensure safe and stable operation of the power system.
When a wind power plant is connected to the grid, various planning schemes exist for the change of a power grid line and a wind power plant access node, and the possibility of oscillation risks of different planning schemes is different, namely, the stability of wind power plant collection systems formed under different planning schemes is different. Currently, most oscillation risk assessment methods for wind power plant collection systems focus on analyzing a secondary/super-synchronous oscillation mechanism of the wind power plant collection systems. Specifically, a frequency scanning method is used for judging whether the wind power plant collection system has an oscillation risk or not by researching a subsynchronous/supersynchronous oscillation mechanism of the wind power plant collection system.
Aiming at wind power station collection systems under different planning schemes, a frequency scanning method can only be used for judging whether oscillation risks exist, but the stability of the wind power station collection systems cannot be evaluated. In practical application, if a plurality of planning schemes have no oscillation risk, the planning scheme with the highest stability is preferably adopted for carrying out the grid-connected operation of the wind power plant, however, the frequency scanning method cannot evaluate the stability of the planning scheme, so that the planning scheme with better stability cannot be selected for the grid-connected operation of the wind power plant.
Disclosure of Invention
In order to solve the problem that a frequency scanning method cannot evaluate the stability of a planning scheme, so that a planning scheme with better stability cannot be selected for actual grid-connected operation of a wind power plant, the application discloses a method and a device for evaluating the oscillation risk of a wind power plant collection system through the following embodiments.
The application discloses in a first aspect a method for assessing oscillation risk of a wind farm collection system, comprising:
acquiring a planning scheme of a wind power plant collection system, wherein the planning scheme of the wind power plant collection system comprises a plurality of power grid planning schemes and a plurality of wind power plant grid-connected planning schemes, the power grid planning schemes comprise grid planning of a power grid and parameters of power equipment in the power grid, and the wind power plant grid-connected planning schemes comprise grid-connected point position planning of a wind power plant and equipment parameters in the wind power plant;
acquiring all resonance modes of a planning scheme of a wind power station collection system aiming at a secondary/super-synchronous frequency band, wherein the resonance modes comprise a resonance mode of each power grid planning scheme and a resonance mode of each wind power grid-connected planning scheme;
obtaining attenuation factors in all resonance modes;
and judging whether each power grid planning scheme and each wind power plant grid-connected planning scheme have oscillation risks or not according to the attenuation factor, and evaluating the stability of each power grid planning scheme and each wind power plant grid-connected planning scheme.
Optionally, the obtaining all resonance modes of the wind farm collection system planning scheme for the secondary/super-synchronous frequency band includes:
acquiring an s-domain equivalent circuit of a wind power plant collection system under each power grid planning scheme aiming at a sub/super synchronous frequency band, and acquiring an s-domain equivalent circuit of the wind power plant collection system under each wind power plant grid-connected planning scheme aiming at the sub/super synchronous frequency band;
constructing an s-domain node admittance matrix of the wind power plant convergence system under each power grid planning scheme according to the s-domain equivalent circuit of the wind power plant convergence system under each power grid planning scheme, and constructing an s-domain node admittance matrix of the wind power plant convergence system under each wind power plant grid-connected planning scheme according to the s-domain equivalent circuit of the wind power plant convergence system under each wind power plant grid-connected planning scheme;
acquiring determinant zero roots of an s-domain node admittance matrix, wherein the determinant zero roots comprise determinant zero roots of an s-domain node admittance matrix of a wind power plant collection system under each power grid planning scheme and determinant zero roots of an s-domain node admittance matrix of the wind power plant collection system under each wind power plant grid-connected planning scheme;
and acquiring all resonance modes of each power grid planning scheme and all resonance modes of each wind power grid-connected planning scheme according to the determinant zero root of the s-domain node admittance matrix.
Optionally, the acquiring attenuation factors in all the resonant modes includes:
acquiring the real part opposite number of determinant zero roots of the s-domain node admittance matrix;
and obtaining attenuation factors of all resonance modes in each power grid planning scheme and attenuation factors of all resonance modes in each wind power grid-connected planning scheme according to the real part opposite number of determinant zero roots of the s-domain node admittance matrix.
Optionally, the determining, according to the magnitude of the attenuation factor, whether there is an oscillation risk in each power grid planning scheme and each wind farm grid-connected planning scheme, and evaluating the stability of each power grid planning scheme and each wind farm grid-connected planning scheme includes:
acquiring minimum attenuation factors of all resonance modes in a target power grid planning scheme and minimum attenuation factors of all resonance modes in a target wind power plant grid-connected planning scheme, wherein the target power grid planning scheme is any one power grid planning scheme, and the target wind power plant grid-connected planning scheme is any one wind power plant grid-connected planning scheme;
judging whether the minimum attenuation factors of all the resonant modes in the target power grid planning scheme are smaller than 0, if so, judging that the target power grid planning scheme has an oscillation risk; judging whether the minimum attenuation factors of all the resonant modes in the target wind power plant grid-connected planning scheme are smaller than 0, if so, judging that the target wind power plant grid-connected planning scheme has an oscillation risk;
evaluating the stability of the target power grid planning scheme according to the minimum attenuation factor of all the resonance modes in the target power grid planning scheme; and evaluating the stability of the target wind power plant grid-connected planning scheme according to the minimum attenuation factors of all the resonance modes in the target wind power plant grid-connected planning scheme.
Optionally, the sub/super-synchronous frequency band ranges from 10Hz to 100 Hz.
The second aspect of the application discloses a device for evaluating oscillation risk of a wind power plant convergence system, which is applied to the method for evaluating oscillation risk of a wind power plant convergence system disclosed in the first aspect of the application, and the device comprises:
the planning scheme acquisition module is used for acquiring a planning scheme of a wind power plant collection system, wherein the planning scheme of the wind power plant collection system comprises a plurality of power grid planning schemes and a plurality of wind power plant grid-connected planning schemes, the power grid planning schemes comprise grid planning of a power grid and parameters of power equipment in the power grid, and the wind power plant grid-connected planning schemes comprise grid position planning of a wind power plant and equipment parameters in the wind power plant;
the system comprises a resonance mode acquisition module, a power grid planning module and a power grid synchronization planning module, wherein the resonance mode acquisition module is used for acquiring all resonance modes of a planning scheme of a wind power station collection system aiming at a sub/super synchronous frequency band, and the resonance modes comprise a resonance mode of each power grid planning scheme and a resonance mode of each wind power grid synchronization planning scheme;
the attenuation factor calculation module is used for acquiring attenuation factors in all the resonance modes;
and the risk evaluation module is used for judging whether each power grid planning scheme and each wind power plant grid-connected planning scheme have oscillation risks or not according to the attenuation factor, and evaluating the stability of each power grid planning scheme and each wind power plant grid-connected planning scheme.
Optionally, the resonant mode obtaining module includes:
the system comprises an s-domain equivalent circuit establishing unit, a sub/super synchronous frequency band acquiring unit and a sub/super synchronous frequency band acquiring unit, wherein the s-domain equivalent circuit establishing unit is used for acquiring an s-domain equivalent circuit of a wind power plant collecting system under each power grid planning scheme aiming at the sub/super synchronous frequency band and acquiring an s-domain equivalent circuit of the wind power plant collecting system under each wind power plant grid-connected planning scheme aiming at the sub/super synchronous frequency band;
the s-domain node admittance matrix construction unit is used for constructing an s-domain node admittance matrix of the wind power plant convergence system under each power grid planning scheme according to the s-domain equivalent circuit of the wind power plant convergence system under each power grid planning scheme, and constructing an s-domain node admittance matrix of the wind power plant convergence system under each wind power plant grid-connected planning scheme according to the s-domain equivalent circuit of the wind power plant convergence system under each wind power plant grid-connected planning scheme;
the zero root calculation unit is used for acquiring a determinant zero root of an s-domain node admittance matrix, wherein the determinant zero root comprises the determinant zero root of the s-domain node admittance matrix of the wind power plant collection system under each power grid planning scheme and the determinant zero root of the s-domain node admittance matrix of the wind power plant collection system under each wind power plant grid-connected planning scheme;
and the resonance mode acquisition unit is used for acquiring all resonance modes of each power grid planning scheme and all resonance modes of each wind power grid-connected planning scheme according to the determinant zero root of the s-domain node admittance matrix.
Optionally, the attenuation factor calculating module includes:
the inverse number calculation unit is used for acquiring the inverse number of the real part of the determinant zero root of the s-domain node admittance matrix;
and the attenuation factor acquisition unit is used for acquiring attenuation factors of all resonance modes in each power grid planning scheme and attenuation factors of all resonance modes in each wind power grid-connected planning scheme according to the real part opposite number of determinant zero roots of the s-domain node admittance matrix.
Optionally, the risk assessment module includes:
the minimum attenuation factor acquisition unit is used for acquiring minimum attenuation factors of all resonance modes in a target power grid planning scheme and minimum attenuation factors of all resonance modes in a target wind power plant grid-connected planning scheme, wherein the target power grid planning scheme is any one power grid planning scheme, and the target wind power plant grid-connected planning scheme is any one wind power plant grid-connected planning scheme;
the risk judgment unit is used for judging whether the minimum attenuation factors of all the resonance modes in the target power grid planning scheme are smaller than 0 or not, and if yes, judging that the target power grid planning scheme has an oscillation risk; judging whether the minimum attenuation factors of all the resonant modes in the target wind power plant grid-connected planning scheme are smaller than 0, if so, judging that the target wind power plant grid-connected planning scheme has an oscillation risk;
the stability evaluation unit is used for evaluating the stability of the target power grid planning scheme according to the minimum attenuation factor in all the resonance modes of the target power grid planning scheme; and evaluating the stability of the target wind power plant grid-connected planning scheme according to the minimum attenuation factor in all the resonance modes of the target wind power plant grid-connected planning scheme.
The embodiment of the application discloses a method and a device for evaluating oscillation risk of a wind power plant collection system. According to the method, each power grid planning scheme and each wind power plant grid-connected planning scheme are analyzed, whether oscillation risks exist in each scheme can be judged, the stability of each scheme can be evaluated, the planning scheme with good stability is selected for actual wind power plant grid-connected operation, and the method has strong engineering practicability.
Drawings
In order to more clearly explain the technical solution of the present application, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious to those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic workflow diagram of a method for evaluating oscillation risk of a wind farm collection system according to an embodiment of the present application;
FIG. 2 is an electrical schematic diagram of a wind farm collection system disclosed in an embodiment of the present application;
fig. 3 is a schematic diagram of a power grid planning scheme disclosed in an embodiment of the present application;
FIG. 4 is a schematic diagram of a wind farm grid-connected planning scheme disclosed in the embodiment of the present application;
fig. 5 is a schematic structural diagram of an apparatus for evaluating oscillation risk of a wind farm collection system according to an embodiment of the present application.
Detailed Description
In order to solve the problem that a frequency scanning method cannot evaluate the stability of a planning scheme, so that a planning scheme with better stability cannot be selected for actual grid-connected operation of a wind power plant, the application discloses a method and a device for evaluating the oscillation risk of a wind power plant collection system through the following embodiments.
The first embodiment of the application discloses a method for evaluating oscillation risk of a wind power plant collection system, and as shown in fig. 1, the method comprises the following steps:
step S11, obtaining a planning scheme of a wind power plant collection system, wherein the planning scheme of the wind power plant collection system comprises multiple power grid planning schemes and multiple wind power plant grid-connected planning schemes, the power grid planning schemes comprise grid planning of a power grid and parameters of power equipment (related transformers, lines and the like) in the power grid, and the wind power plant grid-connected planning schemes comprise grid-connected point position planning of a wind power plant and equipment parameters (installed capacity, equipment types and the like of the wind power plant) in the wind power plant.
And step S12, acquiring all resonance modes of the planning scheme of the wind power station collection system aiming at the sub/super synchronous frequency band, wherein the resonance modes comprise a resonance mode of each power grid planning scheme and a resonance mode of each wind power grid-connected planning scheme.
In step S13, attenuation factors in all the resonance modes are acquired.
And step S14, judging whether each power grid planning scheme and each wind power plant grid-connected planning scheme have oscillation risks or not according to the attenuation factor, and evaluating the stability of each power grid planning scheme and each wind power plant grid-connected planning scheme.
The embodiment of the application discloses a method for evaluating oscillation risk of a wind power plant collection system, and the method comprises the steps of firstly obtaining a planning scheme of the wind power plant collection system, then obtaining all resonance modes of the planning scheme of the wind power plant collection system aiming at a sub/super synchronous frequency band, obtaining attenuation factors in all the resonance modes, judging whether each power grid planning scheme and each wind power plant grid-connected planning scheme have oscillation risk or not according to the attenuation factors, and evaluating the stability of each power grid planning scheme and each wind power plant grid-connected planning scheme. According to the method, each power grid planning scheme and each wind power plant grid-connected planning scheme are analyzed, whether oscillation risks exist in each scheme can be judged, the stability of each scheme can be evaluated, the planning scheme with good stability is selected for actual wind power plant grid-connected operation, and the method has strong engineering practicability.
Further, the acquiring all resonance modes of the planning scheme of the wind power plant collection system for the sub/super synchronous frequency band includes:
and acquiring an s-domain equivalent circuit of the wind power plant collection system under each power grid planning scheme aiming at the sub/super synchronous frequency band, and acquiring the s-domain equivalent circuit of the wind power plant collection system under each wind power plant grid-connected planning scheme aiming at the sub/super synchronous frequency band, wherein the range of the sub/super synchronous frequency band is 10Hz-100 Hz.
And constructing an s-domain node admittance matrix of the wind power plant convergence system under each power grid planning scheme according to the s-domain equivalent circuit of the wind power plant convergence system under each power grid planning scheme, and constructing the s-domain node admittance matrix of the wind power plant convergence system under each wind power plant grid-connected planning scheme according to the s-domain equivalent circuit of the wind power plant convergence system under each wind power plant grid-connected planning scheme.
And acquiring determinant zero roots of the s-domain node admittance matrix, wherein the determinant zero roots comprise the determinant zero roots of the s-domain node admittance matrix of the wind power plant convergence system under each power grid planning scheme and the determinant zero roots of the s-domain node admittance matrix of the wind power plant convergence system under each wind power plant grid-connected planning scheme.
The determinant zero root of the s-domain node admittance matrix is a network resonance mode of the power system, the real part of the determinant reflects the damping of the resonance mode, and the imaginary part of the determinant reflects the frequency of the resonance mode.
And acquiring all resonance modes of each power grid planning scheme and all resonance modes of each wind power grid-connected planning scheme according to the determinant zero root of the s-domain node admittance matrix.
Further, the acquiring attenuation factors in all resonance modes includes:
and acquiring the real part opposite number of the determinant zero root of the s-domain node admittance matrix.
And obtaining attenuation factors of all resonance modes in each power grid planning scheme and attenuation factors of all resonance modes in each wind power grid-connected planning scheme according to the real part opposite number of determinant zero roots of the s-domain node admittance matrix.
Further, the determining whether each power grid planning scheme and each wind farm grid-connected planning scheme have an oscillation risk according to the magnitude of the attenuation factor, and evaluating the stability of each power grid planning scheme and each wind farm grid-connected planning scheme includes:
the method comprises the steps of obtaining the minimum attenuation factors of all resonance modes in a target power grid planning scheme and the minimum attenuation factors of all resonance modes in a target wind power plant grid-connected planning scheme, wherein the target power grid planning scheme is any one power grid planning scheme, and the target wind power plant grid-connected planning scheme is any one wind power plant grid-connected planning scheme.
Judging whether the minimum attenuation factors of all the resonant modes in the target power grid planning scheme are smaller than 0, if so, judging that the target power grid planning scheme has an oscillation risk; and judging whether the minimum attenuation factors of all the resonance modes in the target wind power plant grid-connected planning scheme are smaller than 0, if so, judging that the target wind power plant grid-connected planning scheme has an oscillation risk.
Evaluating the stability of the target power grid planning scheme according to the minimum attenuation factor of all the resonance modes in the target power grid planning scheme; and evaluating the stability of the target wind power plant grid-connected planning scheme according to the minimum attenuation factors of all the resonance modes in the target wind power plant grid-connected planning scheme.
The scheme disclosed in the present application is specifically described by taking a wind power plant collection system modified based on an IEEE 9 node system as an example, an electrical structural schematic diagram of the wind power plant collection system is shown in fig. 2, Bus 1-
Firstly, a planning scheme of a wind power plant collection system is obtained.
And acquiring a power grid planning scheme. Referring to fig. 3, three power grid planning schemes exist in the wind farm collection system, wherein the power grid planning is 1: changing a connecting line between the node 7 and the node 8 and a connecting line between the node 7 and the node 5 into a double-circuit line, wherein the parameters of the added line are the same as those of the original line; and (3) planning a power grid 2: changing the connecting line between the node 9 and the node 8 and the connecting line between the node 9 and the node 6 into a double-circuit line, wherein the parameters of the added line are the same as those of the original line; and (3) planning a power grid: the connecting line between the node 4 and the node 5 and the connecting line between the node 4 and the node 6 are changed into a double-circuit line, and the parameters of the added line are the same as those of the original line.
And acquiring a grid-connected planning scheme of the wind power plant. Referring to fig. 4, three wind power plant grid-connected planning schemes exist in the wind power plant collection system, in fig. 4, a represents wind power plant planning 1, namely, a newly-built wind power plant is connected to a grid at a node 9, installed capacity is 80MW, and a wind power generator set is a direct-drive wind power generator; b represents a wind power plant planning 2, namely a newly-built wind power plant is connected to the grid at a node 6, the installed capacity is 80MW, and the type of a wind turbine generator is a direct-drive wind driven generator; and c, representing a wind power plant planning 3, namely, a newly-built wind power plant is connected to the grid at a node 4, the installed capacity is 80MW, and the type of the wind power generator is a direct-drive wind power generator.
And secondly, analyzing the resonance structure of the wind power plant collection system in the sub/super synchronous frequency band.
Aiming at a sub/super synchronous frequency band (10Hz-100 Hz), an s-domain equivalent circuit of each power grid planning scheme and a wind power plant collection system under the wind power plant grid-connected planning scheme is established, an s-domain node admittance matrix corresponding to the s-domain equivalent circuit is established, and all resonance modes of the wind power plant collection system under different power grid planning schemes and different wind power plant grid-connected planning schemes in the sub/super synchronous frequency band are determined by calculating determinant zero of the s-domain node admittance matrix. The analytical results were as follows:
wind farm collection system under grid planning 11 resonant mode exists in the subsynchronous/supersynchronous frequency band, the resonant frequency is 75.4Hz, and the attenuation factor is 4.6737s-1。
A wind power plant collection system under power grid planning 2 has 1 resonance mode in a sub/super synchronous frequency band, the resonance frequency is 75.3Hz, and the attenuation factor is 4.9277s-1。
1 resonance mode exists in a wind power plant collection system under power grid planning 3 in a sub/super synchronous frequency band, the resonance frequency is 75.4Hz, and the attenuation factor is 3.0634s-1。
A wind power plant collection system under wind power plant grid-connected planning 1 has 2 resonance modes in a sub/super synchronous frequency band, the resonance frequencies are 72.9Hz and 79.2Hz respectively, and the attenuation factors are-1.7845 s respectively-1And 1.9210s-1。
A wind power plant collection system under wind power plant grid-connected
A wind power plant collection system under a wind power plant grid-connected planning 3 has 2 resonance modes in a sub/super synchronous frequency band, the resonance frequencies are 73.5Hz and 78.3Hz respectively, and the attenuation factors are 1.7706s respectively-1And 0.2400s-1。
In the above analysis, the mathematical computation processes of establishing an s-domain equivalent circuit, establishing an s-domain node admittance matrix and calculating a determinant zero root of the s-domain node admittance matrix can be implemented by the prior art, and the embodiment of the present application is not described in detail.
And then, judging and evaluating the subsynchronous/supersynchronous oscillation risk of the wind power plant collection system.
And counting the attenuation factors of the obtained resonance modes, and comparing the attenuation factors to obtain the minimum attenuation factor of all the resonance modes of the wind power plant collection system in the sub/super synchronous frequency band under different power grid planning schemes and different wind power plant grid-connected planning schemes. Statistics shows that the minimum attenuation factors of the wind power plant convergence system under the power grid planning scheme 1-3 and the wind power plant grid-connected planning scheme 1-3 are 4.6737s respectively-1，4.9277s-1，3.0634s-1，-1.7845s-1，0.2430s-1，0.2400s-1. And then, evaluating the subsynchronous/supersynchronous oscillation risk of the wind power plant collection system according to the minimum attenuation factor index. If the minimum attenuation factor is smaller than zero, indicating that a subsynchronous/supersynchronous oscillation risk exists in the wind power plant collection system; if the minimum attenuation factor is larger than zero, it is indicated that the wind power plant collection system does not have subsynchronous/supersynchronous oscillation risks, and the larger the value of the minimum attenuation factor is, the stronger the stability of the system is. Therefore, from the size of the minimum attenuation factor, the wind power plant collection system only has subsynchronous/supersynchronous oscillation risks under the wind power plant grid-connected planning 1, but does not have subsynchronous/supersynchronous oscillation risks under other plans, and the wind power plant collection system has the strongest stability under the power grid planning 2 and the weakest stability under the wind power plant grid-connected planning 3.
And finally, based on the analysis result, specific reference and guidance are provided for the construction of the wind power plant grid-connected project, and the power grid planning scheme with the strongest stability and the wind power plant grid-connected planning scheme can be selected for implementation in the actual wind power plant grid-connected operation.
The following are examples of apparatus disclosed herein that may be used to perform embodiments of the methods of the present application. For details which are not disclosed in the embodiments of the apparatus of the present application, reference is made to the embodiments of the method of the present application.
The second embodiment of the present application discloses a device for evaluating oscillation risk of a wind farm convergence system, which is applied to the method for evaluating oscillation risk of a wind farm convergence system disclosed in the first embodiment of the present application, and as shown in fig. 5, the device includes:
the planning
The resonance
And the attenuation
And the
Further, the resonant
and the s-domain equivalent circuit establishing unit is used for acquiring the s-domain equivalent circuit of the wind power plant collection system under each power grid planning scheme aiming at the sub/super synchronous frequency band and acquiring the s-domain equivalent circuit of the wind power plant collection system under each wind power plant grid-connected planning scheme aiming at the sub/super synchronous frequency band.
And the s-domain node admittance matrix construction unit is used for constructing an s-domain node admittance matrix of the wind power plant collection system under each power grid planning scheme according to the s-domain equivalent circuit of the wind power plant collection system under each power grid planning scheme, and constructing an s-domain node admittance matrix of the wind power plant collection system under each wind power plant grid-connected planning scheme according to the s-domain equivalent circuit of the wind power plant collection system under each wind power plant grid-connected planning scheme.
And the zero root calculation unit is used for acquiring a determinant zero root of an s-domain node admittance matrix, wherein the determinant zero root comprises the determinant zero root of the s-domain node admittance matrix of the wind power plant collection system under each power grid planning scheme and the determinant zero root of the s-domain node admittance matrix of the wind power plant collection system under each wind power plant grid-connected planning scheme.
And the resonance mode acquisition unit is used for acquiring all resonance modes of each power grid planning scheme and all resonance modes of each wind power grid-connected planning scheme according to the determinant zero root of the s-domain node admittance matrix.
Further, the attenuation
and the inverse number calculation unit is used for acquiring the real part inverse number of the determinant zero root of the s-domain node admittance matrix.
And the attenuation factor acquisition unit is used for acquiring attenuation factors of all resonance modes in each power grid planning scheme and attenuation factors of all resonance modes in each wind power grid-connected planning scheme according to the real part opposite number of determinant zero roots of the s-domain node admittance matrix.
Further, the
the minimum attenuation factor obtaining unit is used for obtaining minimum attenuation factors of all resonance modes in a target power grid planning scheme and minimum attenuation factors of all resonance modes in a target wind power plant grid-connected planning scheme, wherein the target power grid planning scheme is any one power grid planning scheme, and the target wind power plant grid-connected planning scheme is any one wind power plant grid-connected planning scheme.
The risk judgment unit is used for judging whether the minimum attenuation factors of all the resonance modes in the target power grid planning scheme are smaller than 0 or not, and if yes, judging that the target power grid planning scheme has an oscillation risk; and judging whether the minimum attenuation factors of all the resonance modes in the target wind power plant grid-connected planning scheme are smaller than 0, if so, judging that the target wind power plant grid-connected planning scheme has an oscillation risk.
The stability evaluation unit is used for evaluating the stability of the target power grid planning scheme according to the minimum attenuation factor in all the resonance modes of the target power grid planning scheme; and evaluating the stability of the target wind power plant grid-connected planning scheme according to the minimum attenuation factor in all the resonance modes of the target wind power plant grid-connected planning scheme.
The present application has been described in detail with reference to specific embodiments and illustrative examples, but the description is not intended to limit the application. Those skilled in the art will appreciate that various equivalent substitutions, modifications or improvements may be made to the presently disclosed embodiments and implementations thereof without departing from the spirit and scope of the present disclosure, and these fall within the scope of the present disclosure. The protection scope of this application is subject to the appended claims.
- 上一篇：一种医用注射器针头装配设备
- 下一篇：一种MEMS衰减器测试装置